I'm off for a trip in less than two weeks. I've decided to shoot film exclusively, even though I've only shot a few rolls. I'm going to take Portra 160 and 400. I shot a roll of 400 a couple weeks ago. I used a light meter and mostly used the settings the light meter gave me in incident mode. I took a few shots where I spot metered the blue sky and whatever I was shooting, and averaged the exposure. All in all most of my shots turned out OK. I've read a little about filters for color film. Are there any must have filters I should be taking for Portra? One of the cities we're visiting is around 10,000 feet so I was thinking about taking a UV filter. I read that's good at elevated positions for haze. I'll be shooting landscapes and city/people shots. I've read that shooting under artificial light requires a filter to remove color cast. I'm going to avoid that by switching to B&W film, if I shoot indoors. I also have a linear polarizer I can take. The reading I've done in terms of film exposure is geared toward B&W. Are there any differences in use of the zone system or exposure in general that I should know about for Portra? I've ordered a few extra rolls of portra and will be practicing with it until I leave. Thanks for any advice you can give.